The γTuRC Revisited: A Comparative Analysis of Interphase and Mitotic Human γTuRC Redefines the Set of Core Components and Identifies the Novel Subunit GCP8

Teixidó-Travesa, Neus; Villén, Judit; Lacasa, Cristina; Bertran, M. Teresa; Archinti, Marco; Gygi, Steven P.; Caelles, Carmé; Roig, Joan; Lüders, Jens

doi:10.1091/mbc.e10-05-0408

Cited by 95 publications

(116 citation statements)

References 41 publications

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“…GCP5 and GCP6 are also present in stoichiometric amounts, but about three times less abundant than GCP2 or GCP3, and GCP4 is nearly twice as abundant as GCP5 and GCP6, but only half as abundant as GCP2 and GCP3. Finally, three proteins associated with the γ‐TuRC, Nedd1 (Haren et al , 2006; Luders et al , 2006) and Mozart 1, and Mozart 2 (Hutchins et al , 2010; Teixido‐Travesa et al , 2010) are similarly abundant as the GCP2 and GCP3 core components of γ‐TuSC. These data extend previous biochemical studies (Murphy et al , 2001; Choi et al , 2010) and support the notion that multiple γ‐TuSCs associate with GCP4, GCP5, and GCP6 into γ‐TuRCs (Kollman et al , 2011; Lin et al , 2015).…”

Section: Resultsmentioning

confidence: 99%

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

et al. 2016

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Centrioles are essential for the formation of centrosomes and cilia. While numerical and/or structural centrosomes aberrations are implicated in cancer, mutations in centriolar and centrosomal proteins are genetically linked to ciliopathies, microcephaly, and dwarfism. The evolutionarily conserved mechanisms underlying centrosome biogenesis are centered on a set of key proteins, including Plk4, Sas‐6, and STIL, whose exact levels are critical to ensure accurate reproduction of centrioles during cell cycle progression. However, neither the intracellular levels of centrosomal proteins nor their stoichiometry within centrosomes is presently known. Here, we have used two complementary approaches, targeted proteomics and EGFP‐tagging of centrosomal proteins at endogenous loci, to measure protein abundance in cultured human cells and purified centrosomes. Our results provide a first assessment of the absolute and relative amounts of major components of the human centrosome. Specifically, they predict that human centriolar cartwheels comprise up to 16 stacked hubs and 1 molecule of STIL for every dimer of Sas‐6. This type of quantitative information will help guide future studies of the molecular basis of centrosome assembly and function.

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Section: Resultsmentioning

confidence: 99%

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

et al. 2016

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“…A missense mutation in GCP2 and downregulation of GCP4 have been shown to change the angle of microtubule branching in Arabidopsis (Nakamura and Hashimoto, 2009;Kong et al, 2010). Of note, human g-TURC was shown to interact with subunits of the chaperonin containing T-complex protein, suggesting that conformation of the nucleation complex may be actively regulated (Teixidó -Travesa et al, 2010). TON2, as a putative B99 subunit of the PP2A, may modulate the conformation of the g-TURC through regulating the phosphorylation status of one or more structural subunits.…”

Section: Ton2 Is a Regulator Of Microtubule Nucleationmentioning

confidence: 99%

TONNEAU2/FASS Regulates the Geometry of Microtubule Nucleation and Cortical Array Organization in Interphase Arabidopsis Cells

2012

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Organization of microtubules into ordered arrays involves spatial and temporal regulation of microtubule nucleation. Here, we show that acentrosomal microtubule nucleation in plant cells involves a previously unknown regulatory step that determines the geometry of microtubule nucleation. Dynamic imaging of interphase cortical microtubules revealed that the ratio of branching to in-bundle microtubule nucleation on cortical microtubules is regulated by the Arabidopsis thaliana B99 subunit of protein phosphatase 2A, which is encoded by the TONNEAU2/FASS (TON2) gene. The probability of nucleation from g-tubulin complexes localized at the cell cortex was not affected by a loss of TON2 function, suggesting a specific role of TON2 in regulating the nucleation geometry. Both loss of TON2 function and ectopic targeting of TON2 to the plasma membrane resulted in defects in cell shape, suggesting the importance of TON2-mediated regulation of the microtubule cytoskeleton in cell morphogenesis. Loss of TON2 function also resulted in an inability for cortical arrays to reorient in response to light stimulus, suggesting an essential role for TON2 and microtubule branching nucleation in reorganization of microtubule arrays. Our data establish TON2 as a regulator of interphase microtubule nucleation and provide experimental evidence for a novel regulatory step in the process of microtubule-dependent nucleation.

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“…These proteins localise a subpopulation of γ-tubulin to existing spindle MTs, and their absence leads to spindles of lower density with an increased astral population (Goshima et al 2008;Hughes et al 2008). Termed Augmin, or HAUS (homologous to Augmin subunits; Lawo et al 2009;Uehara et al 2009), this conserved hetero-octomeric complex has been shown to directly interact with the γTuRC subunit, NEDD1 (Zhu et al 2008), a result that has been independently verified (Teixidó-Travesa et al 2010). Thus, a model has been proposed in which Augmin binds existing spindle MTs during prometaphase and targets active γTuRC, facilitating intraspindle MT nucleation (Goshima et al 2008;Uehara et al 2009) (Fig.…”

Section: Augmin-generated Mtsmentioning

confidence: 98%

50 ways to build a spindle: the complexity of microtubule generation during mitosis

Duncan

Wakefield

2011

Chromosome Res

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The accurate segregation of duplicated chromosomes, essential for the development and viability of a eukaryotic organism, requires the formation of a robust microtubule (MT)-based spindle apparatus. Entry into mitosis or meiosis precipitates a cascade of signalling events which result in the activation of pathways responsible for a dramatic reorganisation of the MT cytoskeleton: through changes in the properties of MT-associated proteins, local concentrations of free tubulin dimer and through enhanced MT nucleation. The latter is generally thought to be driven by localisation and activation of γ-tubulin-containing complexes (γ-TuSC and γ-TuRC) at specific subcellular locations. For example, upon entering mitosis, animal cells concentrate γ-tubulin at centrosomes to tenfold the normal level during interphase, resulting in an aster-driven search and capture of chromosomes and bipolar mitotic spindle formation. Thus, in these cells, centrosomes have traditionally been perceived as the primary microtubule organising centre during spindle formation. However, studies in meiotic cells, plants and cell-free extracts have revealed the existence of complementary mechanisms of spindle formation, mitotic chromatin, kinetochores and nucleation from existing MTs or the cytoplasm can all contribute to a bipolar spindle apparatus. Here, we outline the individual known mechanisms responsible for spindle formation and formulate ideas regarding the relationship between them in assembling a functional spindle apparatus.

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The γTuRC Revisited: A Comparative Analysis of Interphase and Mitotic Human γTuRC Redefines the Set of Core Components and Identifies the Novel Subunit GCP8

Cited by 95 publications

References 41 publications

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

TONNEAU2/FASS Regulates the Geometry of Microtubule Nucleation and Cortical Array Organization in Interphase Arabidopsis Cells

50 ways to build a spindle: the complexity of microtubule generation during mitosis

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